1. Field Of The Invention
This invention relates generally to the field of barcode reading systems and, more specifically, to a barcode reader which accurately reads coding from conventionally printed barcodes and coding from hand-encoded barcodes.
2. Description Of Related Art
Barcodes and their associated reading systems are widely known and used to facilitate manufacturing, shipment and inventory control of diverse goods, to assist in document control, and to aid in many additional tasks. Various barcode reading and laser scanning systems have been developed to scan and decode standard barcode formats and to generate digit representations to be used as inputs, typically, to computers for automatic processing and the like. Conventional barcode reading systems are discussed, for example, in U.S. Pat. No. 4,146,782 to Barnich; U.S. Pat. No. 4,542,528 to Sanner et al.; and U.S. Pat. No. 4,578,571 to Williams.
A number of barcode reading systems are readily available on the market. For example, the following barcode reading systems are, among others, currently available: Epson HX20 by Epson America of Torrance, Calif.; Microwand II by Hand Held Products of Charlotte, N.C.; and Intermec 9400 by Intermec of Seattle, Wash. Each of these barcode reading systems is programmable to read and decode a number of the existing, pre-printed, pre-encoded barcode formats such as UPC, Codabar, and Code 39.
These conventional barcode reading systems scan and read the printed barcode formats and decode the elements (that is, the bars and spaces) of the barcode formats as well known in the art. A typical printed barcode is illustrated in FIG. 1A. In FIG. 1A the printed, pre-encoded barcode 10 is made up of elements consisting of a number bars of varing widths, for example, bars 11, 12, 13, and a number of spaces of varying widths, such as spaces 14, 15, 16, prearranged to represent a string of digits in a known, encoded form. A barcode reading system can be used to scan along a scan track, such as track 17, and read that encoded form. Typically, the scan can be made in either direction.
The conventional reading systems are confined, however, to reading only pre-encoded barcode formats which have been precisely printed as a barcode label. The pre-printed label must contain a predetermined, standard barcode format pattern which is recognizable by the barcode reading systems. Furthermore, the conventional reading systems are susceptible to generating false readings (that is, either a false character or no character at all) if the barcode pattern detected does not fit the precise pattern of known barcode formats. Such false readings can be caused by an imprecisely printed barcode which contains false elements. These false elements are created by extraneous markings, such as an ink spot or a fleck of dirt in a space of the barcode, and by extraneous voids, such as an unintentional void or space in a bar of the barcode. In FIG. 1B the typical printed barcode 10 of FIG. 1A has been modified to show in exaggerated form an extraneous mark 18 in space 14 and an extraneous void 19 in bar 12. If either or both of the extraneous mark and void are detected during a scan by a barcode reader along scan track 17, the conventional barcode reading system will attempt to process the extraneous bars and spaces. That attempt, typically, will result in a false reading or no reading whatsoever of barcode 10.
Being limited to the precisely configured barcode formats readily recognizable by the reading system, the conventional barcode reading systems require barcode formats which must be carefully pre-printed. For accurate reading of the coded information by the conventional systems, these printed, pre-encoded labels must be free from extraneous marks and voids. Furthermore, these systems do not allow the use of a barcode which can be easily marked by the user to contain desired encoded information.
A barcode that is designed to be easily modified by hand to contain valid data using readily available marking equipment, such as pens and pencils, and which can be accurately read by humans and by barcode reading systems would be most useful and have a wide variety of applications. For example, hand-marking or hand-encoding of such a barcode would allow the quick encoding of a variety of data which can be subsequently read by a barcode reading system and verified by the system. The hand-encoded data, once read, can be used as input to computers for automatic processing and the like in the same manner as conventional pre-printed barcodes. For example, a hand-encoded barcode system would be useful for encoding, verifying, and using ZIP Codes.RTM., part numbers, account numbers, and other identification numbers. The hand-encoded barcode system would also be useful for recording and processing survey data, test scores, statistics, and other data. Such a system would be useful in any situation where it is desirable to have a human encode a character or string of characters onto a document, label, package, or the like, which character or string can be easily and accurately identified by humans and by machine for verification and further processing.
While hand-marked, machine readable labels are well known, those labels are not barcode labels. Rather, the known hand-marked labels, often referred to as mark-sense labels, operate in a manner quite different from barcodes. Specifically, the hand-marked material on the mark-sense label is not read and decoded itself; only the relative position of the marking on the label is read and that physical position is then translated into the desired information. In order to obtain accurate decoding of the hand-marked matter, the mark-sense labeling system requires flat sheets of uniform size paper and precise location of the paper within the optical reader so that the relative location of the marking on the sheet can be determined with accuracy for proper translation. Various mark-sense type hand-marked labeling systems are discussed in U.S. Pat. No. 3,528,059 to Spanjersberg, U.S. Pat. No. 3,648,838 to Hiromura, U.S. Pat. No. 3,774,758 to Sternberg, and U.S. Pat. No. 3,783,246 to Bayer.
From the foregoing considerations, it should be apparent that there is a need for an improved barcode reading system in which false readings due to extraneous markings and voids in the barcode are eliminated from the reading of conventional, printed, pre-encoded barcodes. It should also be apparent that there is a need for a barcode that can be easily modified by the user using conventional marking equipment, such as pens, pencils, and the like, to encode a character or string of characters on the barcode and that the hand-encoded barcode be accurately read and decoded by barcode reading systems. Futhermore, it should be apparent that there is a need for a hand-encodable barcode for encoding data on a document or label by a user which encoded data is readable by humans as well as by a wide variety of barcode reading systems. There is also a need for such a barcode system in which the position of the hand-encoded information on the document or label need not be precisely made with reference to any particular physical position on the document or label itself.
It is, thus, intended that the invention provide a method and system for accurately reading encoded information on a barcode.
Another intent is that the invention provide a method and system for reading a barcode and detecting and eliminating false elements from the barcode for accurate decoding of the encoded information on the barcode.
Still another intent is that the invention provide a method and system for easily encoding information on a blank barcode form and accurately reading the encoded information from the marked barcode form by human vision and by barcode reading systems.
Yet another intent is that the invention provide a method and system for reading an encoded string of characters from a plurality of barcodes positioned in a regular order where each barcode represents an encoded character in the string of characters.
It is also intended that the invention provide a barcode label for encoding a string of characters readable by a barcode reading system with accuracy.
Other intentions and features of the invention will further become apparent with reference to the accompanying drawings and the detailed description of the invention or may be learned by practice of the invention.